Inocentes de Belford Roxo was the first school to perform late Sunday at the 72,500-seat Rio Sambodrome, paying a colorful homage to Korean culture in Brazil. The theme called "the Seven confluences of the Han River" invoked the protection of an ancient Korean wind goddess called Yondung Halmoni.

Over the next two nights, a total of 12 schools will parade before a global television audience, competing for the title of Carnival champion.

The VIP guests at the open-air Sambodrome included the 26-year-old American actress Megan Fox, of "Transformers" fame, who was hired to promote Brahma Beer, a popular Brazilian lager.

"I'd love to be Brazilian. I wish I had the Brazilian butt," Fox told reporters. "I'll stay until bedtime. It's an opportunity of a lifetime."

Other celebrities include TV reality show star Kim Kardashian and boyfriend rapper Kanye West; Italian actress Monica Bellucci and her French husband, actor Vincent Cassel; and "Men in Black" star Will Smith, who earlier visited a favela, or shanty town.

In the northeastern city of Salvador, South Korean pop star Psy performed his hit "Gangam Style" to huge crowds Friday alongside Brazilian stars Claudia Leitte, Gilberto Gil and Daniela Mercury.

US movie director Spike Lee was among the celebrity audience.

Unlike the ubiquitous Carnival street parties that are open to all, the Sambodrome parades are mainly for the wealthy and foreign tourists.

Carnival is Brazil's most important festival and is celebrated with equal gusto across the country, including in Sao Paulo, Salvador, Recife, Olinda, Manaus and Porto Alegre.

In the northeastern state of Sergipe, the Carnival celebrations were marred by the death of a 11-year-old child when a driver lost control his sound truck and it collided with a police car, according to press reports.

The reports said 20 other people, including another 11-year-old, were injured in the accident, which was blamed on defective brakes on the truck.

This year there is a special tribute to Koreans to mark the 50th anniversary of their immigration to the country.

Parades in Rio and Sao Paulo are honoring Korean history and technological prowess and the contribution the 50,000-strong Korean community in Brazil has made to this vibrant and racially diverse country of 194 million people.

"It's a historic moment, a recognition of the contribution Koreans have made to Brazilian society," said Marcelo Choi, vice president of the Sao Paulo-based Korean-Brazilian Association.

Dubbed "the greatest show on Earth," the Rio Carnival officially got under way Friday, when the legendary King Momo received a giant key to the city from Mayor Eduardo Paes.

Meanwhile, press reports said authorities have deployed an innovative urinal which can convert urine into electrical energy.

The daily O Globo said the urine collected activates a dynamo which produces energy that can be stored in batteries in a process similar to that used in hydroelectrical power plants.

Officials hope that the device, developed by the cultural group Afro-Reggae, will help curb the practice by revelers to relieve themselves in the streets.

And the energy collected will help fuel the batteries of the huge sound trucks that belt out samba rhythms along Ipanema beach.

Authorities said six million people, including more than 900,000 tourists, were expected to attend the five-day Rio bash.